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https://issues.apache.org/jira/browse/CASSANDRA-8231?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Robert Stupp updated CASSANDRA-8231:
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Attachment: Unsafes.java
Attached {{Unsafes.java}} that I've written some time ago to calculate heap
memory occupied by any object. Although it's a bit over-designed, it solves the
problem of calculating the same object instance twice.
In order to solve the issue of taking irrelevant fields into account, I'd
propose some annotation to be added to those fields - or to provide a set of
classes to exclude from calculation.
> Wrong size of cached prepared statements
> ----------------------------------------
>
> Key: CASSANDRA-8231
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8231
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Reporter: Jaroslav Kamenik
> Assignee: Benjamin Lerer
> Attachments: 8231-notes.txt, Unsafes.java
>
>
> Cassandra counts memory footprint of prepared statements for caching
> purposes. It seems, that there is problem with some statements, ie
> SelectStatement. Even simple selects is counted as 100KB object, updates,
> deletes etc have few hundreds or thousands bytes. Result is that cache -
> QueryProcessor.preparedStatements - holds just fraction of statements..
> I dig a little into the code, and it seems that problem is in jamm in class
> MemoryMeter. It seems that if instance contains reference to class, it counts
> size of whole class too. SelectStatement references EnumSet through
> ResultSet.Metadata and EnumSet holds reference to Enum class...
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